Speech Prosody 2004
Perception experiments using rising and falling F0 slopes in 4 German word-final opening and closing diphthongs show that closing/opening diphthongs support the perception of falling/rising pitch movements. The latter effect is suggested to be enhanced when the initial close vowel quality is retracted and rounded. Hence, the current knowledge of the relationship between intrinsic pitch and vowel quality seems transferable to diphthongs. The estimated intrinsic pitch values of +- 1.5% are better explained by a psychoacoustic pitch-shift than by a process of speech perception compensating for intrinsic F0.
Bibliographic reference. Niebuhr, Oliver (2004): "Intrinsic pitch in opening and closing diphthongs of German", In SP-2004, 733-736.